Transmission

I know this has nothing to do with FJcruisers but here goes.. Thanks in advance.. Today I bought a 96 Toyota 4runner 4x4 sr5 for $1400.. The truck is in great shape btw.. The guy who sold it to me said it "felt like it's slipping" when driving up hill.. He took it to the shop and long story short, they tried to ask more money then quoted.. The shop threw all the parts in the back of the runner and that was the end of it.. Now I have it for a cheap price.. I suspect the slippage is due to a bad torque converter.. Any inputs would be appreciated..